1. Field of the Invention
The present invention relates to content retrieval services provided in a radio access network and more particularly to the caching of retrieved content in a radio access network.
2. Description of the Related Art
The radio access network (RAN) provides for the foundation of modern cellular telephony. The RAN functions to join different end user mobile devices to a core network (CN) such that individuals can enjoy telephonic and data communications wirelessly within a geographic area covered by the various base stations of the radio access network. Generally speaking, the RAN provides the requisite infrastructure to pass both voice and data traffic from the over-the-air medium to both the terrestrial circuit switched communication network and the packet switched data communications network inclusive of the global Internet.
At present, several standards have been implemented in connection with the RAN. Examples include the global system for mobile communications (GSM), the universal mobile telecommunications system (UMTS) and the GSM “Edge” RAN (GERAN). The RAN generally includes multiple different radio network controllers (RNC) each managing a set of base stations providing wireless connectivity to a geographic cell. The entirety of the different RNCs of the RAN are linked to what is known as the cellular data core or CN through a gateway known as the serving generalized radio packet service node (SGSN). The CN provides various services to customers who are connected by the RAN. One of the main functions is to route calls across the public switched telephone network (PSTN). Another is to route data packets onto an Internet protocol (IP) network such as the global Internet so that end users of the RAN can access services provided by a content delivery network (CDN). To that end, the CN includes a gateway known as the gateway GPRS service node (GGSN).
The typical CDN can provide for advanced content delivery services such as content caching and content filtering. Content caching refers to the intermediate temporary storage of previously retrieved content under the assumption that a temporally proximate subsequent request for the content can be satisfied from temporary storage rather than repeating a more time consuming request for content in the CDN. In contrast, content filtering refers to the restriction of the delivery of requested content when the content meets a particular profile such as being published by a particular source or incorporating particular subject matter. In both instances, the packet processing requisite to performing advanced content services often demand that those services are provided within the CN where the communications protocol utilized in the CN is consistent with that of the global Internet—namely the transport control protocol (TCP) over IP.
Even still, some have suggested placing support for content services such as content caching and content filtering within the RAN. In this regard, United States Patent Application Publication No. 20100034089 by Kovvali et al. suggests the placement of content caching services within the RAN and the extraction of TCP/IP payloads from the RAN protocol specific to the RAN. Of note, unlike traditional caching schemes in a traditional computing environments, in a mobile computing environment such as that supported by a RAN, end users traverse the RAN communicating directly with different base stations at different wireless towers along a path of travel. Thus, placing long lasting content services like caching in a base station can result in cached content being rendered largely useless as an end user travels out of range of the wireless tower of the base station.